1. Field of the Invention
The present invention relates to a fuel supply apparatus that includes a high-pressure pump and a controller that controls the high-pressure pump.
2. Description of Related Art
A high-pressure pump has a plunger and a pressurizer chamber, and the plunger is reciprocably movable such that the plunger compresses and pumps fuel that is suctioned by the pressurizer chamber. In the above, fuel compressed in the pressurizer chamber is metered based on valve-closing timing of an inlet valve. In other words, fuel in the pressurizer chamber is returned to a source, from which fuel is suctioned, during the inlet valve is opened after the plunger has started moving upward from a bottom dead center. When the inlet valve is closed, fuel is compressed in the pressurizer chamber.
The inlet valve is contactable with a needle that is fixed with a movable core by welding. Thus, the movable core and the needle move integrally and constitute a movable unit. When a coil is not energized and thereby a magnetic attractive force is not formed, the movable unit is urged toward the inlet valve or toward an opening-side position by a biasing force of a spring. As a result, the inlet valve is opened.
In order to close the inlet valve that is opened as above, the energization is made in order to attract the movable unit toward a closing-side position or to move the movable unit in a direction away from the inlet valve. Due to the above, when the movable unit is displaced to the closing-side position, the inlet valve is closed due to a spring of the inlet valve and due to pressure of fuel in the pressurizer chamber located downstream of the inlet valve (see, for example, JP-A-H9-151768).
However, in the conventional art, when the movable unit is displaced toward the closing-side position, noise may be generated due to collision of the movable unit with another member. Sometimes, the noise may be so large that the noise may be noticeable to a driver disadvantageously.